e2e: revise import restrictions

- test/e2e/framework/*.go should have very minimal dependencies.
  We can enforce that via import-boss.

- What each test/e2e/framework/* sub-package uses is less relevant,
  although ideally it also should be as minimal as possible in each case.

Enforcing this via import-boss ensures that new dependencies get flagged as
problem and thus will get additional scrutiny. It might be okay to add them,
but it needs to be considered.

test/e2e/framework/network/.import-restrictions

@@ -0,0 +1,9 @@
+# This E2E framework sub-package is currently allowed to use arbitrary
+# dependencies, therefore we need to override the restrictions from
+# the parent .import-restrictions file.
+#
+# At some point it may become useful to also check this package's
+# dependencies more careful.
+rules:
+  - selectorRegexp: ""
+    allowedPrefixes: [ "" ]